Magnetic head with planar outrigger

ABSTRACT

A magnetic head includes a substrate having a first tape bearing surface and a second (outrigger) tape bearing surface, preferably with a slot therebetween. A plurality of elements (readers and/or writers) are coupled to the substrate and positioned towards the first tape bearing surface. The first and second tape bearing surfaces lie along planes, the planes being offset from one another spatially and/or angularly. The second tape bearing surface, like typical flat profile heads, induces a small spacing between a tape passing thereover and its tape bearing surface. The second tape bearing surface is positioned below the plane of the first tape bearing surface, thereby creating the proper wrap angle of the tape relative to the first tape bearing surface.

RELATED APPLICATIONS

This application is related to U.S. patent application entitled“MULTI-FORMAT MAGNETIC HEAD” to Biskeborn et al., filed concurrentlyherewith, and U.S. patent application entitled “FLAT PROFILE MAGNETICHEAD” to Biskeborn, filed concurrently herewith.

FIELD OF THE INVENTION

The present invention relates to magnetic head structures, and moreparticularly, this invention relates to a magnetic head structure havinga planar outrigger for establishing a tape wrap angle.

BACKGROUND OF THE INVENTION

FIG. 1 illustrates a traditional flat-lapped bi-directional, two-modulemagnetic tape head 100, in accordance with the prior art. As shown, thehead includes a pair of bases 102, each equipped with a module 104. Thebases are typically “U-beams” that are adhesively coupled together. Eachmodule 104 includes a substrate 104A and a closure 104B with readers andwriters 106 situated therebetween. In use, a tape 108 is moved over themodules 104 along a tape bearing surface 109 in the manner shown forreading and writing data on the tape 108 using the readers and writers106. Conventionally, a partial vacuum is formed between the tape 108 andthe tape bearing surface 109 for maintaining the tape 108 in closeproximity with the readers and writers 106.

Two common parameters are associated with heads of such design. Oneparameter includes the tape wrap angles α_(i), α_(o) defined between thetape 108 and a plane 111 in which the upper surface of the tape bearingsurface 109 resides. It should be noted that the tape wrap angles α_(i),α_(o) includes an inner wrap angle α_(i) which is often similar indegree to an external, or outer, wrap angle α_(o). The tape bearingsurfaces 109 of the modules 104 are set at a predetermined angle fromeach other such that the desired inner wrap angle α_(i) is achieved atthe facing edges. Moreover, a tape bearing surface length 112 is definedas the distance (in the direction of tape travel) between edges of thetape bearing surface 109. The wrap angles α_(i), α_(o) and tape bearingsurface length 112 are often adjusted to deal with various operationalaspects of heads such as that of FIG. 1, in a manner that will soonbecome apparent.

During use of the head of FIG. 1, various effects traditionally occur.FIG. 2A is an enlarged view of the area encircled in FIG. 1. FIG. 2Aillustrates a first known effect associated with the use of the head 100of FIG. 1. When the tape 108 moves across the head as shown, air isskived from below the tape 108 by a skiving edge 204 of the substrate104A, and instead of the tape 108 lifting from the tape bearing surface109 of the module (as intuitively it should), the reduced air pressurein the area between the tape 108 and the tape bearing surface 109 allowsatmospheric pressure to urge the tape towards the tape bearing surface109.

To obtain this desirable effect, the wrap angle α_(o) is carefullyselected. An illustrative wrap angle is about 0.9°±0.2. Note, however,that any wrap angle greater than 0° results in tents 202 being formed inthe tape 108 on opposite edges of the tape bearing surface 109. Thiseffect is a function of tape stiffness and tension. For givengeometrical wrap angles for example, stiffer tapes will have largertents 202.

If the wrap angle α_(i), α_(o) is too high, the tape 108 will tend tolift from the tape bearing surface 109 in spite of the vacuum. Thelarger the wrap angle, the larger the tent 202, and consequently themore air is allowed to enter between the tape bearing surface 109 andtape 108. Ultimately, the forces (atmospheric pressure) urging the tape108 towards the tape bearing surface 109 are overcome and the tape 108becomes detached from the tape bearing surface 109.

If the wrap angle α_(i), α_(o) is too small, the tape tends to exhibittape lifting 205, or curling, along the side edge of the tape bearingsurface 109 as a result of air leaking in at the edges and tapemechanical effects. This effect is shown in FIG. 2B. Particularly, theedges of the tape curl away from the tape bearing surface 109, resultingin edge loss or increased spacing between the edges of the tape and thetape bearing surface 109. This is undesirable, as data cannot reliablybe written to the edges of a tape in a system subject to edge loss.

Additionally, the tape lifting 205 results in additional stress atpoints 206 which, in turn, may cause additional wear. Further augmentingsuch tape lifting 205 is the fact that the tape 108 naturally hasupturned edges due to widespread use of technology applied in the videotape arts.

The external wrap angles α_(o) are typically set in the drive, such asby rollers. The offset axis creates an orbital arc of rotation, allowingprecise alignment of the wrap angle α_(o). However, situations arisewhere rollers may not be the most desirable choice to set the externalwrap angles α_(o). For example, rollers require extra headroom in adrive, particularly where they are adjustable. Additionally, rollers,particularly adjustable roller systems, may be more expensive to installin the drive. A further drawback of this approach is mechanicalalignment cannot be completed independent of signal read readiness.

One proposed solution, which is less expensive than implementingadjustable rollers, is to precisely install fixed rollers in the drive,the mounting of the rollers being fixedly set to provide about thedesired wrap angle. (Some implementations further require adjusting thehead during drive build to obtain the desired wrap angles.) However,with normal machining tolerances, the resultant wrap angle can vary byas much as ±0.5°. This is well outside the tolerances required forreliable reading and writing. For instance, using the example of a 0.9°ideal wrap angle, at the low end, the wrap angle would be 0.4°. Such alow wrap angle will result in edge loss. At the high end, the wrap anglewould be 1.4°, which results in the tape lifting from the tape bearingsurface.

There is accordingly a clearly-felt need in the art for a tape headassembly in which the critical wrap angles are fixed on the head itself,or fixed relative to the head itself. These unresolved problems anddeficiencies are clearly felt in the art and are solved by thisinvention in the manner described below.

SUMMARY OF THE INVENTION

A magnetic head in one embodiment includes a substrate having a firsttape bearing surface and a second (outrigger) tape bearing surface wherethe first and second tape bearing surfaces are separated by a slot. Aplurality of elements (readers and/or writers) are coupled to thesubstrate and positioned towards the first tape bearing surface. Thefirst and second tape bearing surfaces lie along substantially parallelplanes, the planes being offset from one another. The second tapebearing surface induces a small spacing between a tape passing thereoverand its tape bearing surface. The second tape bearing surface ispositioned below the plane of the first tape bearing surface and thetrailing edge of the second tape bearing surface is positioned at aprescribed distance from the leading edge of the first tape bearingsurface, thereby creating the proper wrap angle of the tape relative tothe first tape bearing surface.

Preferably, the plane of the second tape bearing surface is positionedbelow the plane of the first tape bearing surface, for example in arange of about 0.004 to about 0.014 mm below the plane of the first tapebearing surface.

A slot may be defined between the first and second tape bearingsurfaces. The width of the slot between the surfaces is, for example, ina range of about 0.3 to about 1.0 mm.

Again, a first wrap angle is defined between the plane of the first tapebearing surface and a tape traveling from the second tape bearingsurface to the first tape bearing surface, the first wrap angle beingdetermined by a position of the second tape bearing surface relative tothe first tape bearing surface. An illustrative first wrap angle is in arange of about 0.7° to about 1.1°.

A second wrap angle may also be defined between the plane of the secondtape bearing surface and a tape traveling towards the second tapebearing surface. The second wrap angle is less critical, and may be, forexample, greater than about 0.1° and less than about 2°.

One or more additional elements (readers and/or writers) may optionallybe coupled to the module towards the second tape bearing surface.

The head may include a pair of modules coupled together. In such anembodiment, the second module may include a second substrate having athird tape bearing surface and a fourth tape bearing surface, and aplurality of elements coupled to the substrate and positioned towardsthe first tape bearing surface, wherein the third and fourth tapebearing surfaces lie along substantially parallel planes, the planes ofthe third and fourth tape bearing surfaces being offset from oneanother. Preferably, the planes of the first and third tape bearingsurfaces are angled relative to one another for setting internal wrapangles of the tape with respect to the first and third tape bearingsurfaces. The internal wrap angels may be similar to the first wrapangle described above.

In another embodiment, a magnetic head includes a substrate having atape bearing surface, and a plurality of elements coupled to thesubstrate and positioned towards the tape bearing surface. An outriggeris held in a fixed position relative to the substrate, the outriggeralso having a tape bearing surface lying along a plane that is offsetfrom the substrate tape bearing surface. Again, the two tape bearingsurfaces are separated by a gap or slot.

The outrigger may or may not be integral to the substrate. For example,the outrigger can be adhesively coupled to the substrate. In anotherembodiment, the outrigger is not coupled directly to the substrate. In afurther embodiment, the outrigger tape bearing surface is parallel to atape oriented at a desired wrap angle relative to the substrate tapebearing surface. In yet another embodiment, the outrigger tape bearingsurface is angled from the substrate tape bearing surface by greaterthan a desired wrap angle of a tape relative to the substrate tapebearing surface.

In yet another embodiment, the second tape bearing surface is offset asabove, but no slot or gap is formed between the first and second tapebearing surfaces. In this embodiment, the height difference between theplanes is smaller and may be, e.g., about 0.002 to about 0.004 mm.

A tape drive system includes a head as recited above, a drive mechanismfor passing a magnetic recording tape over the head, and a controller incommunication with the head. The system may further include an outertape guide for setting a wrap angle of the tape relative to the second(outrigger) tape bearing surface.

Methods for forming such heads are also presented. One illustrativemethod for forming a head includes forming elements on a substrate, theelements being selected from a group consisting of readers, writers, andcombinations thereof. The substrate is cut into rows, each row having afirst portion and a second portion. A slot is formed in each row betweenthe first portion and the second portion, and a height of the secondportion of the row is reduced. The row is cut into individual modules.The modules may then be coupled together to form a head.

Other aspects and advantages of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and advantages of the presentinvention, as well as the preferred mode of use, reference should bemade to the following detailed description read in conjunction with theaccompanying drawings.

Prior Art FIG. 1 illustrates a traditional flat-lapped magnetic tapehead, in accordance with the prior art.

Prior Art FIG. 2A is an enlarged view of Circle 2A of FIG. 1, showing afirst and second known effect associated with the use of the head ofFIG. 1.

Prior Art FIG. 2B is a cross-sectional view taken along Line 2B of FIG.2A, showing a third known effect associated with the use of the head ofFIG. 1.

FIG. 3 is a side view of a magnetic tape head with integral outriggersaccording to one embodiment.

FIG. 4 is a side view of a magnetic tape head with outriggers formed asseparate pieces and coupled to the substrate according to oneembodiment.

FIG. 5 is a side view of a magnetic tape head with outriggers notcoupled directly to the substrate according to one embodiment.

FIG. 6 is a side view of a magnetic tape head having an outrigger with atape bearing surface that is generally aligned with a tape set at apreferred wrap angle relative to the tape bearing surface adjacent theelements.

FIG. 7 is a side view of a magnetic tape head having an outrigger with atape bearing surface that is angled relative to the tape bearing surfaceadjacent the elements, such that an overwrap is created.

FIG. 8 is a perspective view of a section of a thin film wafer accordingto one embodiment.

FIG. 9 is a perspective view of an array of closures.

FIG. 10 is a perspective view depicting coupling of the array ofclosures to the section of wafer.

FIG. 11 is a perspective view of the array of closures coupled to thesection of wafer.

FIG. 12 is a perspective view of the closures coupled to the section ofwafer upon removing a top portion of the array.

FIG. 13 is a side view depicting cutting of a row from a section ofwafer.

FIG. 14 is a side view of a row cut from a wafer.

FIG. 15 is a perspective view of a row cut from a wafer.

FIG. 15A is a cross sectional view of the row of FIG. 15 taken alongLine 15A-15A of FIG. 15.

FIG. 16 is a perspective view of a row with a trench cut therein.

FIG. 17 is a perspective view of a row with an outrigger formed thereon.

FIG. 18 is a perspective view of a die cut from a row.

FIG. 19 is a perspective view of a die coupled to a U-beam.

FIG. 20 is a side view of a module with an integrated outrigger.

FIG. 21 is a side view of a magnetic tape head with outriggers havingelongated tape bearing surfaces according to one embodiment.

FIG. 22 is a schematic diagram of the tape drive system.

BEST MODE FOR CARRYING OUT THE INVENTION

The following description is the best mode presently contemplated forcarrying out the present invention. This description is made for thepurpose of illustrating the general principles of the present inventionand is not meant to limit the inventive concepts claimed herein.Further, particular features described herein can be used in combinationwith other described features in each and any of the various possiblecombinations and permutations.

In the drawings, like and equivalent elements are numbered the samethroughout the various figures.

The embodiments described below disclose a new head design thattolerates a wider range of initial tape wrap angles in a drive withoutsacrificing drive performance. This is accomplished by equipping thehead with a novel type of outriggers, as explained below. The outriggerscontrol the critical wrap angles within the head, and at the same timeprevent the ‘external’ variations due to head positioning or externalguide positioning errors from affecting the critical wrap angles, thusallowing a wider variation in drive-level wrap. This invention enablespurely mechanical or datum-based positioning of a head in a drive.

FIG. 3 illustrates an embodiment of a flat profile tape head 300 havingintegral outriggers 302. As shown the head includes opposing modules304, each module 304 having a substrate 306, elements (readers and/orwriters) 308, and a closure 310. The modules 304 are coupled togethersuch that the tape bearing surfaces 312 of the modules 304 are offset insuch a way that internal wrap angles α_(i) are defined between themodules 304. Cables 311 or other suitable wiring connect the elements toa controller, and read and write electronics.

Outriggers 302 are formed on each module 304. The outriggers 302 controlthe outer wrap angle α_(o) of the tape 315 relative to the tape bearingsurfaces 312 adjacent the elements 308. Note that while the term “tapebearing surface” appears to imply that the surface facing the tape 315is in physical contact with the tape bearing surface, this is notnecessarily the case. Rather, it is more typical that a portion of thetape is in contact with the tape bearing surface, constantly orintermittently, and other portions of the tape ride above the tapebearing surface on a layer of air, sometimes referred to as an “airbearing”.

As shown, each outrigger 302 has a flat tape bearing surface 314 thatinduces a small spacing between a tape 315 passing thereover and itstape bearing surface 314. When the tape 315 moves across the head, airis skived from below the tape 315 by a skiving edge 318, and instead ofthe tape 315 lifting from the tape bearing surface 314 of the module (asintuitively it should), the reduced air pressure in the area between thetape 315 and the tape bearing surface 314 allows atmospheric pressure tourge the tape towards the tape bearing surface 314. The outrigger 302 ispositioned below the plane 317 of the tape bearing surface 312 adjacentthe elements 308, thereby creating the proper wrap angle α_(o) of thetape 315 relative to the tape bearing surface 312 adjacent the elements308.

In this embodiment, the tape bearing surfaces 312, 314 lie on parallelplanes 317, 319, but are offset in a direction perpendicular to theplanes 317, 319. Where the tape bearing surfaces 312, 314 lie alongparallel yet offset planes, intuitively, the tape should peel off of thetape bearing surface 314 of the outrigger 302. However, the vacuumcreated by the skiving edge 318 of the outrigger 302 has been found byexperimentation to be sufficient to keep the tape adhered to the tapebearing surface 314 of the outrigger 302. The trailing end 320 of theoutrigger 302 (the end from which the tape leaves the outrigger 302) isthe reference point which defines the wrap angle α_(o) over the tapebearing surface 312 adjacent the elements 308. Thus, the outer wrapangle α_(o) is approximately tan⁻¹(δ/W) where δ is the height differencebetween the planes and W is the width of the slot as shown in FIG. 20.

An interesting characteristic of this and the next embodiment is thatthe tape does not tack down on the trailing outrigger. This in turnreduces wear on the trailing outrigger. A further benefit of thisembodiment is that, because the outrigger 302 is formed directly on thesubstrate, the outer wrap angle α_(o) can be cut by machining surface314 (just as the inner wrap angles α_(i) are fixed when the modules 304are coupled together).

While the outrigger 302 is preferably integrally formed on the module304, alternatively, the outrigger 302 can be a separate piece mounted tothe module 304, not directly coupled to the module 304 but held inposition relative thereto by mounting hardware in the drive, etc. FIG. 4illustrates an embodiment 400 where the outrigger 302 is formed from aseparate piece adhesively coupled to the substrate. The outrigger 302shown in FIG. 4 is directly coupled to the module 304, and can be formedof a material similar to or the same as the substrate 306. Any suitablecoupling mechanism can be implemented to couple the outrigger 302 to themodule 304, including but not limited to adhesives, screws, clamps, etc.

FIG. 5 illustrates an embodiment 500 where the outrigger 302 is notmounted directly to the substrate 306, but is mounted to the samestructure 502 to which each module 304 is coupled. As mentioned above,it is most preferable that the outrigger 302 is fixedly coupled inrelation to the substrate, so that the outer wrap angles α_(o) remainfixed regardless of initial outer wrap angle α_(oo) of the tapeapproaching the outrigger 302.

In embodiments where the outrigger 302 has no elements, the initial wrapangle α_(oo) is less critical, and so greater tolerances are permitted.Particularly, tape wrap variations at the outer (skiving) edge 319 ofthe outrigger 302 do not change the internal wrap angle α_(i). Asuggested initial wrap angle α_(oo) for the outrigger 302 is 0.6°±0.5°or 0.7°±0.5°, but can be as high as 2° or higher. The inventors havefound that only a very slight wrap angle α_(oo) (e.g., 0.1°) need bepresent in order to create the desired tacking of the moving tape to thetape bearing surface 314. Wraps below 0.1 degrees have a higher risk ofthe tape popping off the outrigger 302, and wraps above 1.1 degrees mayproduce an undesirable stress level in the tape. In addition, the lengthof the tape bearing surface 314 in the direction of tape motion shouldpreferably be longer than the tent length 202 (FIG. 2A) to ensure propertack down of the tape.

With continued reference to FIG. 3, the initial wrap angle α_(oo) can beachieved by providing a datum in the head 300 assembly itself and thenpositioning the head 300 to datums in the drive. Alternatively, alocating fixture, consisting, for example, of a beam that straddles theguides on either side of the head 300 that has features for contactingthe outrigger surfaces, may be used. Another technique is determiningthe wrap angles on the outriggers 302 via a laser beam. Another methodwould be to use adjustable rollers in conjunction with a laser or afixture to set the wrap angle α_(oo) (still not using tape signals).Additionally, for compatibility the head 300 can be used in drivesalready having signal-based wrap.

In some embodiments, the outrigger 302 may itself include supplementalread and/or write elements 510, as shown in FIG. 5. Examples ofsupplemental writing include erase writing, servo writing, etc. For suchapplications, control of the initial wrap angle α_(oo) is less critical.An example of supplemental reading is reading the tape prior to writingand/or primary readback. One skilled in the art will appreciate thatonly the leading outrigger 302 may provide these functions, as the tapewill not adhere to the trailing outrigger 302 (if present) until thetape direction is reversed.

The remaining discussion will assume that no elements are present on theoutrigger 302, though one skilled in the art will appreciate thatadditional elements can be added to the outrigger(s) 302 of thefollowing embodiments in a manner similar to that described above.

The tape bearing surface of the outrigger need not necessarily beparallel to and below the plane of the tape bearing surface adjacent tothe elements, but can be offset angularly as well as spatially. In theembodiment 600 shown in FIG. 6, the outrigger 302 has a tape bearingsurface 314 that is parallel to the tape at the desired wrap angle α_(o)relative to the tape bearing surface 312 adjacent to the elements 308.

FIG. 7 illustrates a further embodiment, where the outrigger 302 has atape bearing surface 314 that is angled relative to the tape bearingsurface 312 adjacent to the elements 308 by greater than the desiredwrap angle α_(o) of a tape relative to the tape bearing surface 312adjacent the elements 308. This orientation of the tape bearing surfaces312, 314 is generally referred to as an overwrap configuration, becausethe tape “wraps over” the trailing edge 330 of the outrigger 302.

In the embodiments shown in FIGS. 6 and 7, the outrigger 302 ispreferably not formed integrally on the substrate, as the inventors havefound that though the general shape is relatively easy to form on thesubstrate, setting the offset of the trailing edge of the tape bearingsurface 314 of the outrigger 302 relative to the tape bearing surface312 adjacent the elements 308 is very difficult to achieve.Particularly, the error in the offset distance is greater thantolerances allow. Due to the difficulties encountered when attempting toform such embodiments as an integral portion of the substrate 306, theseembodiments are preferably formed of a separate outrigger 302 that ismounted to the substrate 306, overall module 304, or head 300.

One advantage provided by the embodiments of FIGS. 6 and 7 is that theinternal wrap angle α_(o) of a tape relative to the tape bearing surfaceadjacent the elements on a particular module is defined by theoutrigger. An additional advantage of the embodiments of FIGS. 6 and 7is that the initial wrap angle of the tape approaching the leadingoutrigger is less critical, as adherence of the tape to the outriggertape bearing surface is not required.

To create the outrigger as an integral portion of the module, as in theembodiment shown in FIG. 3, the module is generally formed as in atypical fabrication process but with some additional steps, as set forthbelow. According to one preferred method for forming the head, a wafercontaining multiple “chips” each having read and/or write transducers(elements) is formed by traditional thin film processing. The thin filmwafer is cut into rectangular sections, sometimes called quads. A thinfilm wafer can be any type of composite or composition capable ofcontaining devices therein, but should be hard and capable of supportingthe tape without exhibiting excessive wear.

FIG. 8 illustrates a section 800 of a thin film wafer according to oneembodiment. As shown, the section 800 includes a plurality of rows 802of devices that will eventually be sliced and diced to form a head ordie. Each row 802 may contain multiple head images. Thus, while each rowcontains two head images in this figure, rows may generally have six ormore head images.

FIG. 9 shows an array 900 of closures 902 that will be bonded to asection 800 of the wafer. FIG. 10 illustrates how the array 900 isbonded to a section 800.

FIG. 11 depicts the array 900 of closures 902 bonded to the section 800of wafer. A top portion 904 (FIG. 9) of the array 900 of closures 902may be removed prior to slicing the section 800 into rows 802. Grindingmay be used to remove the top portion 904 of the array 900. FIG. 12shows the closure 902 and section 800 with the top portion of the array900 of closures 902 removed. The portions of the closure 902 remainingafter processing support the tape as the tape passes over the head toprotect the delicate devices in the head from wear, similar to the waythe tape 315 engages the head 300 shown in FIG. 3. Next, the row on theend of the quad 1200 may be lapped to give the final tape bearingsurface.

As shown in FIG. 13, a blade 1300 is used to slice rows from eachsection 800 by cutting through the closure 902 and section 800 such thatopposite sides of the blade 1300 engage an equal surface area of theclosure 902. In other words, the blade 1300 fully engages the closure902. This in turn helps keep the blade 1300 straight during cutting, asequal forces exist on either side of the blade 1300.

FIG. 14 illustrates a row sliced from the section 800. Upon slicing, twopieces of closure material may remain coupled to the row. One portion1400 of the closure material is desired and will function to engage thetape when the row is placed in a tape head. The other portion 1402 ofthe closure material, referred to as a sliver 1402, is removed.

FIGS. 15 and 15A show a row after the sliver 1402 is removed. As shownin FIG. 16, a slot 1600 is formed in the row such as by grinding,sawing, laser cutting, etc. The slot 1600 gives the row a generallyU-shaped profile at this point in the process.

Next, as shown in FIG. 17, the outrigger portion 1704 of the row isground with a precision grinder. One type of grinder includes an opticalor mechanical sensor that detects a first surface 1702 (such as the tapebearing surface of the module adjacent the elements) and, using thatsurface 1702 as a reference, grinds another surface 1704 to a desiredoffset from the reference, preferably to within 1-2 microns of thetarget depth. Such grinders are available from Toshiba and CranfieldEngineering.

The rows are then diced into individual thin film chips, or dies 1800,using traditional methods. See FIG. 18, which illustrates one die 1800.Each die 1800 is coupled to a U-beam 1900, as shown in FIG. 19. TheU-beams 1900 are eventually coupled together to form a head.

An illustrative thickness of the wafer perpendicular to its face isabout 1.2 mm. Another illustrative thickness of the wafer is about 2 mm.An illustrative width W of the slot is between about 0.3 mm and about 1mm, though 0.6 mm and above is generally preferred. The tape bearingsurface of the outrigger is positioned below the plane of the tapebearing surface of the substrate adjacent the elements. The distance δbetween the planes of the tape bearing surfaces will depend on the slotwidth and desired wrap angle. A general range is about 0.004 to about0.014 mm between the planes of the tape bearing surfaces. The depth ofthe slot is sufficient to allow escape of air from the skiving edge ofthe substrate positioned adjacent the elements. In general, the slotwill be deeper than the tape bearing surface of the outrigger. Anillustrative depth of the slot as measured from the tape bearing surfaceof the substrate adjacent the elements is about 0.009 mm to about 0.25mm. Taken another way, an illustrative depth of the slot as measuredfrom the tape bearing surface of the outrigger is about 0.001 mm toabout 0.24 mm. An illustrative width L of the outrigger is about 0.28mm, but in general should be greater than about the width of the tent(202 in FIG. 2A) of the tape to allow sufficient tack down length.

In one embodiment, the desired wrap angle of the tape relative to thetape bearing surface of the substrate adjacent the elements is about0.9°±0.1°. FIG. 20 sets forth several illustrative dimensions of amodule 304 according to an exemplary embodiment. The width of the wafer(substrate 306) is about 1.2 mm. The width of the slot 1600 is about 0.6mm. This width is suggested as it tends to provide a good balancebetween obtaining the proper wrap angles, liftoff tendency on theoutrigger 302, and tape stiffness effects. The width of the outrigger isabout 0.28 mm. A depth of the slot is about 0.18 mm as measured from thetape bearing surface 312 adjacent the elements 308. The tape bearingsurface 314 of the outrigger is about 0.009±0.002 mm below the plane ofthe tape bearing surface 312 adjacent the elements 308.

One skilled in the art will appreciate that the dimensions given aboveand other places herein are presented by way of example only and can bemade larger or smaller per the design and fabrication constraints,performance considerations, etc.

In other embodiments, where the outrigger is not integral to thesubstrate, the head can be created in a conventional manner, with theadditional step of adhering the outrigger to the substrate or mountingthe outrigger to the head so that it is held in fixed relation to themodule. These steps may be automated or performed by human labor.

FIG. 21 depicts a further embodiment 2100 where the second tape bearingsurface 314 is offset from the first tape bearing surface 312 as in theembodiments of FIGS. 3 and 4 above, but no slot or gap is formed betweenthe first and second tape bearing surfaces. In this embodiment, theheight difference between the planes is smaller and may be, e.g., about0.002 to about 0.004 mm.

Any of the above embodiments or combinations of portions thereof canalso be applied to any type of magnetic heads and magnetic recordingsystems, both known and yet to be invented. For example, the teachingsherein are easily adaptable to interleaved heads, which typicallyinclude opposing modules each having an array of alternating readers andwriters configured to provide read-while-write capability.

FIG. 22 illustrates a simplified tape drive which may be employed in thecontext of the present invention. While one specific implementation of atape drive is shown in FIG. 22, it should be noted that the embodimentsof the previous figures may be implemented in the context of any type oftape drive system.

As shown, a tape supply cartridge 2220 and a take-up reel 2221 areprovided to support a tape 2222. These may form part of a removablecassette and are not necessarily part of the system. Guides 2225 guidethe tape 2222 across a preferably bidirectional tape head 2226, of thetype disclosed herein. Such tape head 2226 is in turn coupled to acontroller assembly 2228 via an MR connector cable 2230. The controller2228, in turn, controls head functions such as servo following, writebursts, read functions, etc. An actuator 2232 controls position of thehead 2226 relative to the tape 2222.

A tape drive, such as that illustrated in FIG. 22, includes drivemotor(s) to drive the tape supply cartridge 2220 and the take-up reel2221 to move the tape 2222 linearly over the head 2226. The tape drivealso includes a read/write channel to transmit data to the head 2226 tobe recorded on the tape 2222 and to receive data read by the head 2226from the tape 2222. An interface is also provided for communicationbetween the tape drive and a host (integral or external) to send andreceive the data and for controlling the operation of the tape drive andcommunicating the status of the tape drive to the host, all as will beunderstood by those of skill in the art.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of a preferred embodiment shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims and theirequivalents.

1. A magnetic head, comprising: a substrate having a planar first tapebearing surface and a planar second tape bearing surface; a plurality ofelements coupled to the substrate and positioned towards the first tapebearing surface, the elements being selected from a group consisting ofreaders, writers, and combinations thereof, wherein the first and secondtape bearing surfaces lie along substantially parallel planes, theplanes being offset from one another, wherein the second tape bearingsurface has a skiving edge for skiving air from a tape arriving frombelow the plane of the second tape bearing surface and engaging theskiving edge, thereby creating a reduced air pressure in an area betweenthe tape and the second tape bearing surface that allows atmosphericpressure to urge the tape towards the second tape bearing surface alonga length of the second tape bearing surface from the skiving edge to atrailing end of the second tape bearing surface positioned opposite theskiving edge, the tape being about parallel to the second tape bearingsurface when traveling thereacross in a direction towards the first tapebearing surface, the tape traveling above the plane of the second tapebearing surface towards the first tape bearing surface after thetrailing end of the second tape bearing surface, wherein the first tapebearing surface has a skiving edge for skiving air from a tape arrivingfrom below the plane of the first tape bearing surface from the secondtape bearing surface and engaging the skiving edge of the first tapebearing surface, thereby creating a reduced air pressure in an areabetween the tape and the first tape bearing surface that allowsatmospheric pressure to urge the tape towards the first tape bearingsurface alone a length of the first tape bearing surface from theskiving edge thereof to a trailing end of the first tape bearing surfacepositioned opposite the skiving edge of the first tape bearing surface,wherein a second wrap angle is defined between the plane of the secondtape bearing surface and a tape traveling towards the second tapebearing surface, the second wrap angle being greater than about 0.1°. 2.The head as recited in claim 1, wherein the plane of the second tapebearing surface is positioned below the plane of the first tape bearingsurface.
 3. The head as recited in claim 2, wherein the plane of thesecond tape bearing surface is positioned in a range of about 0.004 toabout 0.014 mm below the plane of the first tape bearing surface.
 4. Thehead as recited in claim 1, wherein a slot is defined between the firstand second tape bearing surfaces.
 5. The head as recited in claim 4,wherein a width of the slot is in a range of about 0.3 mm to less than1.0 mm.
 6. The head as recited in claim 1, wherein a first wrap angle isdefined between the plane of the first tape bearing surface and a tapetraveling from the second tape bearing surface to the first tape bearingsurface, the first wrap angle being determined by a position of thesecond tape bearing surface relative to the first tape bearing surface.7. The head as recited in claim 6, wherein the first wrap angle is in arange of about 0.7° to about 1.1°.
 8. The head as recited in claim 1,wherein the substrate is a single piece of contiguous material, thefirst and second tape bearing surfaces being integral to the singlepiece.
 9. The head as recited in claim 1, wherein the second wrap angleis less than about 2°.
 10. The head as recited in claim 1, wherein atleast one additional element is coupled to the module towards the secondtape bearing surface.
 11. The head as recited in claim 1, furthercomprising a second substrate having a third tape bearing surface and afourth tape bearing surface, and a plurality of elements coupled to thesubstrate and positioned towards the first tape bearing surface, whereinthe third and fourth tape bearing surfaces lie along substantiallyparallel planes, the planes of the third and fourth tape bearingsurfaces being offset from one another.
 12. The head as recited in claim11, further comprising a first closure extending from the firstsubstrate and forming a portion of the first tape bearing surface, and asecond closure extending from the second substrate and forming a portionof the third tape bearing surface, wherein the planes of the first andthird tape bearing surfaces are angled relative to one another forsetting internal wrap angles of the tape with respect to the first andthird tape bearing surfaces.
 13. The head as recited in claim 12,wherein a first wrap angle is defined between the plane of the firsttape bearing surface and a tape traveling from the second tape bearingsurface to the first tape bearing surface, wherein the first wrap angleis about equal to the internal wrap angles.
 14. A tape drive system,comprising: a head as recited in claim 1; a drive mechanism for passinga magnetic recording tape over the head; and a controller incommunication with the head.
 15. The tape drive system as recited inclaim 14, further comprising an outer tape guide for setting a wrapangle of the tape relative to the second tape bearing surface, the wrapangle being greater than about 0.1°.
 16. The head as recited in claim 1,further comprising a closure coupled to the substrate and having a tapebearing surface coplanar and contiguous with the first tape bearingsurface of the substrate.